Genotypes and Phenotypes of Staphylococcus aureus from Bulk Tank Milk on Organic Dairy Farms in Vermont

摘要

Staphylococcus aureus remains an important mammary pathogen on dairy farms, including organic farms (Cicconi-Hogan et al., 2013). Multilocus sequence typing (MLST) is a discriminatory and repeatable epidemiologic tool that facilitates comparison of S.aureus isolates (Zadoks et al., 2011). Some S. aureus strain types (ST) or clonal complexes (CC) tend to be host specific, such as the sequence types ST97, ST151, ST 479, and ST705 are commonly isolated from cases of bovine mastitis (Zadoks et al., 2011). In vitro phenotypes associated with bovine S. aureus mastitis isolates include hemolysis patterns, biofilm formation potential and antimicrobial susceptibility (Devriese, 1984; Tremblay et al., 2013; van den Borne et al., 2010). The objective of thisstudy was to evaluate the association between S. aureus ST and biofilm formation or antimicrobial susceptibility for isolates from bulk tank milk on organic dairy farms in Vermont.